Liver kinase B1 is required for thromboxane receptor-dependent nuclear factor-κB activation and inflammatory responses

J He, Y Zhou, J Xing, Q Wang, H Zhu… - … , and vascular biology, 2013 - Am Heart Assoc
J He, Y Zhou, J Xing, Q Wang, H Zhu, Y Zhu, MH Zou
Arteriosclerosis, thrombosis, and vascular biology, 2013Am Heart Assoc
Objective—Thromboxane A2 receptor (TPr) has been reported to trigger vascular
inflammation. Nuclear factor κ B (NF-κB) is a known transcription factor. The aims of the
present study were to determine the contributions of NF-κB activation to TPr-triggered
vascular inflammation and elucidate the mechanism (s) underlying TPr activation of NF-κB.
Approach and Results—The effects of TPr activators,[1S-[1alpha, 2alpha (Z), 3beta (1E,
3S*), 4alpha]]-7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo [2.2. 1] hept-2-yl]-5 …
Objective
Thromboxane A2 receptor (TPr) has been reported to trigger vascular inflammation. Nuclear factor κ B (NF-κB) is a known transcription factor. The aims of the present study were to determine the contributions of NF-κB activation to TPr-triggered vascular inflammation and elucidate the mechanism(s) underlying TPr activation of NF-κB.
Approach and Results
The effects of TPr activators, [1S-[1alpha,2alpha(Z),3beta(1E,3S*), 4alpha]]-7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (I-BOP) and U46619, on NF-κB activation, phosphorylation of rhoA/rho-associated kinases and liver kinase B1, cell adhesion and migration, proliferation, and endothelium-dependent vasorelaxation were assayed in cultured human umbilical vein endothelial cells, human monocytes, or isolated mouse aortas. Exposure of human umbilical vein endothelial cells to TPr agonists I-BOP and U46619 induced dose-dependent and time-dependent phosphorylation of inhibitor of κB α in parallel with aberrant expression of inflammatory markers cyclooxygenase-2, inducible nitric oxide synthase, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1. Inhibition of NF-κB by pharmacological or genetic means abolished TPr-triggered expression of inflammatory markers. Consistently, exposure of human umbilical vein endothelial cells to either I-BOP or U46619 significantly increased phosphorylation of inhibitor of κB α, IkappaB kinase, rhoA, rho-associated kinases, and liver kinase B1. Pretreatment of human umbilical vein endothelial cells with the TPr antagonist SQ29548 or rho-associated kinases inhibitor Y27632 or silencing of the LKB1 blocked TPr-enhanced phosphorylation of inhibitor of κB α and its upstream kinase, IkappaB kinase. Finally, exposure of isolated mouse aortas to either U46619 or I-BOP enhanced NF-κB activation and vascular inflammation in parallel with reduced endothelium-dependent relaxation in intact vessels.
Conclusions
TPr stimulation instigates aberrant inflammation and endothelial dysfunction via rho-associated kinases/liver kinase B1/IkappaB kinase-dependent NF-κB activation in vascular endothelial cells.
Am Heart Assoc